2009 Annual Science Report
University of Hawaii, Manoa Reporting | JUL 2008 – AUG 2009
Characterizing Formation Pathways for 1st Generation Ices
Molecular chemistry can provide insight into the physical processes at the earliest stages of star birth, when
molecular cloud cores collapse to form protostellar condensations.
Dust particles in the dense clouds accrete molecules from the gas,
resulting in the growth of ice mantles that eventually get
transported into the protostellar environment. It is here, that the
warm and dense environments of star forming regions promote a rich
chemistry that creates complex prebiotic compounds and a small
fraction of this material ends up as planets. Understanding the dominant chemical
pathways and the composition of the first ice mantles formed in starless molecular
clouds allows to better interpret the physical effects of star formation (i.e., temperature, radiation, etc.) on molecular cloud material.
Using Keck and Gemini (ground-based observatories on Mauna Kea), we observed the absorption spectra in the 3-to-5 micron range of 31 field stars that lie behind the LDN 673 molecular cloud. This large sample was extracted from a well characterized quiescent molecular cloud and any differences, similarities, and trends in the ice abundances can be studied exclusively as a function of cloud environment, namely the role of increasing extinction in promoting grain surface chemistry. The data set was completed and released to us in October 2008. We are currently analyzing the data and developing an ice map of the molecular cloud.